It appears to be a paralyzingcounterpart to PoisonPowder and Sleep Powder, as the accuracy, Contest group, appeal, effects, Japanese names and animation are the same or very similar. They are also usually learned at the same level or in a similar pattern.

A tornado of topaz mist comes out of the hole on Vileplume's head, paralyzing anyone who comes into contact with the dust, or Vileplume releases a ball of orange dust into the air that lands on the opponent, paralyzing them.

Trivia

Most of Stun Spore's in-game descriptions state that it mayparalyze the target. The word choice is likely alluding to its 75% accuracy, since it will always paralyze the target if the move is successful.